First quote the idea of the big guy: use the filter filter to set the encoding format
post encoding is easy:
1. In the XML configuration file
<filter> <filter-name>Hello</filter-name> <filter-class>com.jde.filter.HelloFilter</filter-class> <init-param> <param-name>encode</param-name> <param-value>UTF-8</param-value> </init-param> </filter>
2. Then in the filter method init()
The configured encoding UTF-8 can be obtained through filterConfig.getFilterName()
//String name = filterConfig.getFilterName();
//Get the specified encoding configured in XML---->trim() cuts whitespace characters.
String encode = filterConfig.getInitParameter("encode").trim();
//If encode is not empty, let him assign a value
if(encode != null && !"".equals(encode)){
this.encode = encode;
}
3. If you want to modify the encoding of the get request method, you need to create a class inheritance: HttpServletRequestWrapper
Need to override the getParameter() method!
Likewise, you can create a multi-argument constructor.
@Override
public String getParameter(String name) {
//The parent class getParameter is called to get the passed parameters
String value = super.getParameter(name);
/*
* 1. Start transcoding,
* 2. Define an intermediate variable valueLast
*/
String valueLast = null;
//Assign valueLast
try {
/*
* Determine whether value is null,
* If it is null, then assign null to valueLast,
* If not, decode the content of value with ISO-8859-1, and then use UTF-8 to return a string to valueLast after encoding
*/
valueLast = value==null?null:new String(value.getBytes("ISO-8859-1"),encode);
} catch (UnsupportedEncodingException e) {
e.printStackTrace ();
}
4. Then it is to be configured in the doFilter() method, if it is the post method directly
//Set the post method to modify the code of the whole station request.setCharacterEncoding(this.encode);
If the request method is: get
Then you need:
if("get".equalsIgnoreCase(method)){
//Create request decoration implementation class
req = new myW(req,this.encode);
}
System.out.println("chain agrees to execute downward!");
chain.doFilter(req, response);
....
OK---
Paste the entire code:
jsp code:,
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<h1>Use post to send data</h1>
<form action="/HelloFilter/servlet/HelloServlet" method="post">
姓名：<input name="username" type="text">
<input type="submit" value="提交">
</form>
<h1>Use get to send data</h1>
<a href="/HelloFilter/servlet/HelloServlet?username=Hello everyone">Click</a>
</body>
</html>
Code for the HttpServletRequestWrapper subclass:
package com.jde.filter;
import java.io.UnsupportedEncodingException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
public class myW extends HttpServletRequestWrapper {
//Set the default encoding property of the request decorator
private String encode;
// no-argument constructor
public myW(HttpServletRequest request) {
super(request);
}
//Define a parameterized constructor
public myW(HttpServletRequest request, String encode) {
super(request);
this.encode = encode;
}
/*
* Override getparameter
*/
@Override
public String getParameter(String name) {
//The parent class getParameter is called to get the passed parameters
String value = super.getParameter(name);
/*
* 1. Start transcoding,
* 2. Define an intermediate variable valueLast
*/
String valueLast = null;
//Assign valueLast
try {
/*
* Determine whether value is null,
* If it is null, then assign null to valueLast,
* If not, decode the content of value with ISO-8859-1, and then use UTF-8 to return a string to valueLast after encoding
*/
valueLast = value==null?null:new String(value.getBytes("ISO-8859-1"),encode);
} catch (UnsupportedEncodingException e) {
e.printStackTrace ();
}
return valueLast;
}
}
filter code:
package com.jde.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
public class HelloFilter implements Filter {
private String encode;
//log out
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
System.out.println("start....");
//Set the post method to modify the code of the whole station
request.setCharacterEncoding(this.encode);
/*
* Now force the request method
*/
HttpServletRequest req = (HttpServletRequest)request;
//Get the request method, whether it is get or post
String method = req.getMethod();
System.out.println("Print request method: "+method);
/*
* 1. If the request method is get, enter it and start to set the encoding method of get
* 2. Case insensitive when comparing
*/
if("get".equalsIgnoreCase(method)){
//Create request decoration implementation class
req = new myW(req,this.encode);
}
System.out.println("chain agrees to execute downward!");
chain.doFilter(req, response);
}
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("Filter was created...");
//String name = filterConfig.getFilterName();
//Get the specified encoding configured in XML---->trim() cuts whitespace characters.
String encode = filterConfig.getInitParameter("encode").trim();
//If encode is not empty, let him assign a value
if(encode != null && !"".equals(encode)){
this.encode = encode;
}
}
}